Infrared Image Furnace Research Articles

Effect of Interface Property on the Agglomeration Characteristic of Inclusions in High Al Steel with Different Al Contents

Herein, a 3D stability diagram is established in the AlON system. Based on that, four sets of experiments with different Al contents are designed to prepare different inclusions. Subsequently, the agglomeration behavior of inclusion is observed in situ by using confocal laser scanning microscopy (CLSM) combined with an infrared image furnace. The sample with inclusions is heated to melt and the agglomeration behavior of inclusion is recorded by the CRT monitor of CLSM. The calculated agglomeration force of inclusion shows that when the Al content increases from 0.5 to 3 pct, the agglomeration force of Al2O3 inclusions decreases from 7.2 × 10−16 ≈ 6.0 × 10−14 N to 1.2 × 10−16 ≈ 3.2 × 10−15 N. As the Al content increases from 6.5 to 10 pct, the agglomeration force of AlN inclusions increases from 2.2 × 10−17 ≈ 1.1 × 10−15 N to 1.7 × 10−16 ≈ 7.9 × 10−15 N. The theoretical calculation also shows that the agglomeration force of Al2O3 inclusions decreases and that of AlN inclusions increases with the increasing Al content. When the Al content is >4.7 pct, the agglomeration force of AlN inclusions is larger than that of Al2O3 inclusions.

Effects of suspension processing conditions on the multi-scale structural changes of photocured SiO2 bodies during sintering process: An operando observation using optical coherence tomography

The relationships between the processing methods of photocurable SiO2 suspensions, powder dispersion states, material processability, and the structural changes of photocured SiO2 bodies during their sintering into transparent glass components were investigated. Using an inter-particle photo-cross-linkable SiO2 suspension as the model system, three series of suspensions with different dispersion states but the same compositions were designed via different powder processing routes. The effects of the differences in the particle dispersion states on the real-time multi-scaled structural changes of photocured bodies during sintering were elucidated via operando observation using an optical coherence tomography (OCT) system equipped with an infrared image furnace. The photocured body prepared using the well-dispersed suspension starts to gradually densify from the outside, finally reaching a fully densified state. Furthermore, during the densification process, the photocured body warped, and then the structure recovered owing to the earlier densification at the bottom region of the sample, where the infrared light was focused for heating. Contrastingly, when the suspension contained agglomerates, an un-densified area was observed in the sintering material in the form of microstructures, which remained in the material after sintering. The in-line transparency of the sintered SiO2 material was consistent with those of the microstructures observed using OCT.

Single-Crystal Growth of Sr2RuO4 by the Floating-Zone Method Using an Infrared Image Furnace with Improved Halogen Lamps

We report the single-crystal growth of the unconventional superconductor Sr2RuO4, on which research has reached a turning point recently. In order to optimize the quality of crystals grown by the floating-zone method using an infrared image furnace, we focus on an improvement of the structure of the filament in the halogen lamps. By reducing the thickness of the total filament, the form of the molten zone was narrowed. More importantly, the molten zone was observed to be more stable during the growth process. Finally, we obtained the crystals with a length of 12 cm. Additionally, the grown crystal has high quality, displaying the 1.5 K transition temperature expected only for the purest crystals. We also discuss the availability of the newly developed halogen lamps.

Large Size Single Crystal Growth of Ti4O7 by the Floating-Zone Method

We report the growth of large size Ti4O7 single crystals by the floating-zone method using an infrared image furnace. By employing a high rotation rate of the seed rod, we improved the temperature ...

Investigation of metallurgical phenomena related to process and product development by means of High Temperature Confocal Scanning Laser Microscopy

An increased interest for high temperature metallurgical processes appeared during the last decades, in order to achieve the high quality requirements in steel products. A defined steel cleanness and microstructure essentially influence the final product quality. The high temperatures involved in metallurgical processes and the lack of in situ observations do not only complicate the verification of simulation model predictions but also make significant conclusions regarding the industrial processes difficult. For that reason, new tools and techniques are necessary to develop. By combining the advances of a laser, confocal optics and an infrared image furnace, the High Temperature Confocal Scanning Laser Microscopy (HTCSLM) is a strong tool which enables high temperature in situ observations of different metallurgical phenomena. Next to solidification processes and phase transformations also the behavior of inclusions at different interfaces in the system steel-slag-refractory can be observed. The present study focuses on the aspects of inclusion agglomeration in the liquid steel and the inclusion behavior at the steel/refractory interface in two different steel grades. Out of the obtained experimental data, attraction forces are calculated and compared. This information provides an important basis for a better understanding of inclusion behavior in industrial processes and the therewith related process optimization, like for example the clogging phenomenon during continuous casting.

Single-Crystal Growth of a Perovskite Ruthenate SrRuO3 by the Floating-Zone Method

We report single-crystal growth of a perovskite ruthenate SrRuO3 by the floating-zone method using an infrared image furnace. By employing a cold trap for the growth, we prevented the evaporated RuO2 from coating the inner surface of a quartz tube and were thereby able to maintain a stable molten zone during the growth. Powder X-ray and Laue diffraction measurements confirmed the quality of the grown single crystal. The crystal was cut into a 1.4 mm × 1.4 mm × 3.0 mm rectangle that was characterized by magnetic susceptibility, magnetization, and specific heat measurements. The crystal showed a ferromagnetic transition with a Curie temperature of 163.5 K, and the coercive field was as low as 0.004 T. The residual resistivity was 1.05 μΩ cm, corresponding to a residual resistivity ratio of 192. These results indicate that the grown crystal is high-quality. Electrical resistivity measurements show temperature-squared behavior, revealing that a Fermi-liquid-like electron–electron scattering is dominant. Toget...

Single-crystal growth of Mg- and Ni-doped chain compound SrCuO2 by the traveling-solvent floating-zone method and chain breaking effect induced by the dopants

Pure and doped high-quality single-crystals of the non-congruently melting chain compound SrCuO2 were grown in an infra-red image furnace using the traveling solvent floating zone technique. The growth conditions, together with the characterization of the grown single crystals by optical microscopy, EDX, X-ray powder diffraction and magnetization in the 2–300K temperature range are presented. Doping by Mg2+ (S=0) and Ni2+ (S=1) on the Cu2+ (S=½) sites leads to breaking of the chains of the structure in finite segments.

Wood-Templated CeO2 as Active Material for Thermochemical CO Production

Heterogeneous reactions benefit from active materials with accessible pores and high surface areas. Such materials can be synthesized, for example, by templating methods. Particularly high surface areas are obtained in nanoporous solids. However, the solid walls surrounding nanopores also have typical dimensions in the nanometer range, and these walls are prone to sintering at high temperatures, reducing the active surface area. Here we demonstrate wood templating as an approach that balances accessible porosity with higher thermal stability, using cerium oxide as a representative active material in a high-temperature process: thermochemical CO production. Wood-templated CeO2 (WT CeO2) was synthesized via the Pechini method and annealed at 1200–1500 °C, temperatures suitable for the thermochemical reduction of CeO2. The pore structure consists of interconnected channels with pores tens of micrometers in diameter and micrometer-thick walls. The WT CeO2 maintained its interconnected pore structure with surface areas of ∼0.1 m2 g–1 at temperatures up to 1400 °C, despite significant grain growth. The cycling performance of the annealed WT CeO2 was tested by conducting 21 cycles in an infrared imaging furnace. WT CeO2 samples were reduced at temperatures from 1200 to 1500 °C and reoxidized with CO2 at 800 °C. The presintered WT CeO2 samples retained their structure after cycling. With a reduction temperature of 1400 °C, the WT CeO2 achieved CO production rates 6 times higher than nonporous CeO2 compared at the same nonstoichiometry δ (for CeO2−δ). CO production rates are comparable to those obtained with electrospun Zr-doped CeO2 fibers under similar conditions.

Direct STM Studies of CO Adsorption and Oxidation on Pt(111) Electrodes: (1) Electrochemical Measurements and STM Observations

The mechanism of the adsorption and electrochemical oxidation of CO in electrolyte solutions on Pt catalysts has long been studied. Significantly enhanced CO oxidation has been observed in the presence of a CO adlayer preadsorbed at low electrode potentials, giving rise to a well-known prepeak in the CO stripping voltammogram prior to the main CO oxidation peak. Evidence was presented to show an effect of the defect sites on the Pt(111) surface on the characteristics of the prepeak.1) Wieckowski and coworkers extensively investigated the role of defects for the CO electrooxidation in alkaline media,2) and Strmcnik et al. reported that platinum surfaces modified with platinum nanoislands have a high activity for CO oxidation at prepeaks.3) In the present study, the CO electrooxidation at Pt(111)-oriented surfaces with steps is investigated by combining electrochemical measurements and electrochemical (EC) STM.3) Single-crystal beads of Pt were made by crystallization of molten balls formed at the end of Pt wires in a hydrogen–oxygen flame. The (111)-oriented planes were exposed by mechanical polishing. The surfaces were then heat-treated in an infrared imaging furnace and cooled under hydrogen. The electrochemical measurements were carried out in 0.1 M HClO4. EC-STM measurements were carried out using a CO- or N2-saturated solution under a CO atmosphere. For the reference electrode, an RHE was used. Fig. 1(a) shows voltammograms obtained in CO-saturated HClO4 on Pt(111) with (111) steps The CO oxidation started at ca. 0.4 V in the prepeak region. After the electrochemical potential was cycled between 0.05 and 0.95 V 30 times, the prepeak observed at lower potentials completely disappeared.4) By examining CO stripping voltammograms with and without CO in solution (Fig. 1(b)), it was suggested that the origin of this prepeak is the oxidation of bulk CO in solution. Fig. 2 shows the STM images at a (111) step on Pt(111) recorded before and after the potential cycling. The (2x2) structure of the CO adlayer is clearly seen. Before the potential cycling, the step has defects, forming a zigzag line (Fig. 2(a)). After the potential cycling, the step became very straight running in the [110] direction, with no defects observed (Fig. 2(b)). The structure change at steps should be related to the reactivity. On Pt(20 19 19) with (100) steps, the prepeak was very small, and after the potential cycles disappeared completely. Fig. 3(a) shows an STM image on Pt(20 19 19) before cycling. The step is straight, which might explain the small prepeak on pristine Pt(20 19 19). Fig. 3(b) shows an image after the potential cycles. The (111) microsteps were introduced to the (100) step, and the step became zigzagged. From the results on Pt(111)-related surfaces with different steps, it can be understood that not every defect is active for the electrooxidation of CO in solution.This research was supported by MEXT and NEDO, Japan.ReferencesA. Lopez-Cudero, A. Cuesta, and C. Gutierrez, J. Electroanal. Chem. 579, 1 (2005).J. S. Spendelow, Q. Xu, J. D. Goodpaster, P. J. A. Kenis, and A. Wieckowski, J. Electrochem. Soc., 154, F238, (2007)D. S. Strmcnik, D. V. Tripkovic, D. van der Vliet, K.-C. Chang, V. Komanicky, H. You, G. Karapetrov, J. P. Greeley, V. R. Stamenkovic, and N. M. Markovic, J. Am. Chem. Soc., 130, 15332 (2008).J. Inukai, D. A. Tryk, T. Abe, M. Wakisaka, H. Uchida, and M. Watanabe, J. Am. Chem. Soc ., 135, 1476 (2013).

Ceria-based electrospun fibers for renewable fuel production via two-step thermal redox cycles for carbon dioxide splitting.

Zirconium-doped ceria (Ce(1-x)Zr(x)O2) was synthesized through a controlled electrospinning process as a promising approach to cost-effective, sinter-resistant material structures for high-temperature, solar-driven thermochemical redox cycles. To approximate a two-step redox cycle for solar fuel production, fibrous Ce(1-x)Zr(x)O2 with relatively low levels of Zr-doping (0 < x < 0.1) were cycled in an infrared-imaging furnace with high-temperature (up to 1500 °C) partial reduction and lower-temperature (∼800 °C) reoxidation via CO2 splitting to produce CO. Increases in Zr content improve reducibility and sintering resistance, and, for x≤ 0.05, do not significantly slow reoxidation kinetics for CO production. Cycle stability of the fibrous Ce(1-x)Zr(x)O2 (with x = 0.025) was assessed for a range of conditions by measuring rates of O2 release during reduction and CO production during reoxidation and by assessing post-cycling fiber crystallite sizes and surface areas. Sintering increases with reduction temperature but occurs primarily along the fiber axes. Even after 108 redox cycles with reduction at 1400 °C and oxidation with CO2 at 800 °C, the fibers maintain their structure with surface areas of ∼0.3 m(2) g(-1), higher than those observed in the literature for other ceria-based structures operating at similarly high temperature conditions. Total CO production and peak production rate stabilize above 3.0 mL g(-1) and 13.0 mL min(-1) g(-1), respectively. The results show the potential for electrospun oxides as sinter-resistant material structures with adequate surface area to support rapid CO2 splitting in solar thermochemical redox cycles.

Visual analysis of solidification and δ–γ transformations in steels

The theory of solidification of steels and the kinetics of austenite to α-ferrite phase transformation were extensively studied; however, comparatively, little information is available concerning the kinetics of the δ-ferrite to austenite transformation due to the difficulty of making in situ observations. In the present study, a laser scanning confocal microscopy with an infrared image furnace was implemented with which the in situ observations at the high temperature of the dynamic behaviour of the δ/γ grain nucleation and growth and interphase boundaries of the steels are made possible. The solidification mode of the carbon steel and the austenitic stainless steel during welding can be directly observed, and the definitive sequence of phase transformation that led to the final microstructure was detected in real time. Finally, new experimental results will be presented and compared with previous studies.

Nonlinear electrical grain boundary properties in proton conducting Y–BaZrO3supporting the space charge depletion model

The overall proton conductivity of polycrystalline acceptor-doped BaZrO(3) is limited by the high resistivity of its grain boundaries. To investigate the nature of the electrical response of the grain boundaries as a function of the DC bias, Y-doped BaZrO(3) ceramics with a very large grain size (up to 200 μm) have been prepared in an infrared image furnace. The grains are so large that even individual grain boundaries can be addressed by microelectrodes. DC voltage-dependent resistance and capacitance of the grain boundaries are discussed in terms of the space charge model. The results corroborate carrier depletion (OH(O)˙, h˙, V(O)˙˙) as origin of the pronounced grain boundary resistance. This picture fits well into the space charge scenario found for various related oxide materials, and leads to strategies for improving grain boundary conductivity.

Evolved gas analysis–ion attachment mass spectrometric analysis of decacarbonyl dimanganese pyrolysis

Evolved gas analysis–ion attachment mass spectrometric analysis of the principal species produced by the pyrolysis of Mn2(CO)10 in an infrared image furnace indicated the presence of Mn(CO)5 in the gas phase. This observation indicates that Mn2(CO)10 was in equilibrium with Mn(CO)5. We also studied the temperature dependence of the mass spectrum to obtain information about the kinetics of the Mn2(CO)5 dissociation reaction. From the temperature dependence of the peak for Mn(CO)5Li+ (m/z 202), we calculated the apparent activation energy of Mn(CO)5 dissociation from solid Mn2(CO)10. The calculated activation energy (274.57 kJ/mol) is compared with previously reported experimental and calculated values of Mn–Mn bond dissociation energies.

&lt;i&gt;In Situ&lt;/i&gt; Observation of Solidification Behavior in a Q235 Steel by Using Electric Pulse Modification

In the unmodified and EP-modified melt of Q235 steel, the solidification behavior including the nucleation and growth of crystals has been observedin situby use of a confocal scanning laser microscope combined with an infrared image furnace, and meanwhile, described the characteristic of phase transformation. The result shows that the every stage of phase transformation is advanced; the phase transformation time is shortened, and temperature is reduced during heating proceeds. On the other hand, it can be observed that the nucleation density of solid phase increases and has an even distribution among the liquid phase.

Evolved gas analysis–ion attachment mass spectrometric observation of Mn(CO)5 and Mn2(CO)9 radicals produced by Mn2(CO)10 pyrolysis

Evolved gas analysis–ion-attachment mass spectrometry (EGA–IAMS) indicates that Mn(CO)5 and Mn2(CO)9 free radicals are produced in the gas phase by pyrolysis of Mn2(CO)10 in an infrared image furnace. The Li+-adduct mass spectra of the pyrolysis products contained peaks at m/z 202 and 369 for Mn(CO)5Li+ and Mn2(CO)9Li+, respectively, providing direct evidence that d-metal complex radicals were formed in the furnace. We studied the effect of temperature on the rate of production of the radicals, and confirmed the presence of the compounds Mn(CO)5 and Mn2(CO)9, which were reported in earlier studies based on electron-impact mass spectrometry, electron spin resonance spectroscopy, and Fourier transform infrared spectroscopy.

Optical observation of real materials using laser scanning confocal microscopy Part 1 – techniques and observed examples of microstructural changes

Owing to the good thermal response of an infrared image furnace, the thermal cycle of welds (weld metal or heat affected zone) can be reproduced, while a laser scanning confocal microscope has a suitable light source and optical geometry for observing metal irradiated at high temperatures. The combination of an infrared image furnace and a laser scanning confocal microscope provides a useful tool for determining the microstructural changes in metals at the micrometre scale during the thermal cycle of welding. The technique of using such a combined system is called high temperature laser scanning confocal microscopy. Both macro‐ and microviews expand the understanding of the microstructural formation of welds and are useful in developing microstructure control methods. This is the first part of a report on the application of laser scanning confocal microscopy to observe microstructural changes for various types of steel samples and thermal cycles. The micro‐ or macroviews of different microstructural formations are presented, including the solidification cell, austenite from δ‐ferrite, pearlite, martensite, Widmanstätten ferrite and bainite.

鉄の浸炭初期過程に及ぼす炭素結晶性の影響

Iron carburization is one of the most important reactions in iron making process. If the rate and efficiency of carburization reaction are increased, energy consumption of the process will be reduced to a large extent. The purpose of this study is to clarify the effect of carbon structure on initial iron carburization behavior for suggestion of effective carbon utilization in iron making process. Samples of different carbon structures were prepared by heat treatment of CH 4 decomposed carbon at various temperatures. Carbon structures of prepared carbon samples were analyzed by a Raman spectroscopy. For experiments, high-purity iron samples directly-contacted with carbon were prepared. A laser microscope combined with an infrared image furnace was used for heating of the sample and in-situ observation of carburization phenomena. Carbon concentration profile in iron sample was analyzed by a wavelength dispersion type electron probe micro analyzer. The results of this work showed that primary Fe-C liquid formation temperature became lower from 1 439 to 1 431 K with use of lower crystallization carbon. It was indicated that utilization of the lower crystallization degree of carbon structure causes formation of primary Fe-C liquid at the lower temperature.

Effect of Carbon Structure Crystallinity on Initial Stage of Iron Carburization

Iron carburization is one of the most important reactions in iron making process. If the rate and efficiency of carburization reaction are increased, energy consumption of the process will be reduced to a large extent. The purpose of this study is to clarify the effect of carbon structure on initial iron carburization behavior for suggestion of effective carbon utilization in iron making process. Samples of different carbon structures were prepared by heat treatment of CH 4 decomposed carbon at various temperatures. Carbon structures of prepared carbon samples were analyzed by a Raman spectroscopy. For experiments, high-purity iron samples directly-contacted with carbon were prepared. A laser microscope combined with an infrared image furnace was used for heating of the sample and in-situ observation of carburization phenomena. Carbon concentration profile in iron sample was analyzed by a wavelength dispersion type electron probe micro analyzer. The results of this work showed that primary Fe-C liquid formation temperature became lower from 1 439 to 1 431 K with use of lower crystallization carbon. It was indicated that utilization of the lower crystallization degree of carbon structure causes formation of primary Fe-C liquid at the lower temperature.

Effect of atmosphere and catalyst on reducing bisphenol A (BPA) emission during thermal degradation of polycarbonate

Bisphenol A (BPA), a well-known endocrine disruptor, is one of the major products in the thermal degradation of polycarbonate (PC) and is also leached out from various PC products. Because of the high acute toxicity of BPA, reducing BPA production during degradation of PC is an important topic. A combined Infrared Image Furnace with Ion attachment mass spectrometry technique was used to investigate the evolution of BPA from a PC sample during heating in either nitrogen or air atmosphere and with or without a CuCl 2 catalyst. Thermal treatment in the presence of CuCl 2, in nitrogen atmospheres and at lower degradation temperatures, substantially reduced the BPA emission.

In situ observation of phase transformation in Fe–0.15C binary alloy

Time-resolved high resolution synchrotron X-ray diffraction has been used to conduct in situ studies of the temporal evolution of α → γ and γ → α transformations. Moreover, high temperature laser scanning confocal microscopy with an infrared imaging furnace has been used to directly observe the morphological development of γ → α transformations. It makes possible that phase transformation can be identified in real time during heating and continuously cooling process. Phase transformation process of Fe–0.15C binary alloy was analyzed as a combination of these two experimental facilities.